The present invention relates to a pump which is driven by a motor and which sucks and discharges liquid, and to a liquid supply apparatus having the pump.
The pump includes an impeller which sucks and discharges liquid, a motor unit which drives the impeller, and a parting plate which is disposed between the impeller and the motor unit and has a function for parting therebetween. The pump also includes a case in which a pump chamber is formed. The impeller is accommodated in the pump chamber. The pump also includes a suction port which is connected to the case and through which liquid is sucked, and a discharge port through which liquid is discharged.
The case is provided with a discharge passage through which liquid including gas is discharged into the discharge port from the pump chamber.
As disclosed in Japanese Patent Application Laid-open No. H10-227291 (Patent Document 1), in the pump having the above-described structure, liquid including gas such as air is introduced into the pump chamber from the suction port by the rotating impeller. The liquid is sent to the discharge passage, and gas and liquid are separated in the discharge passage. As a result, gas separated above the liquid by a specific gravity difference and a portion of liquid are discharged from the discharge port.
If this pump is used, the pump can include a so-called self-support function capable of maintaining a supply function of liquid by separating gas from the liquid including the gas which flows into the pump chamber and by discharging the gas.